Odd running problem
Discussion
I have an intermittent problem with my 5.0.There is more than one symptom so here goes.
First it will run fine and then not idle, you can press the clutch while driving and it will stall. Secondly it will suddenly behave as if its has a rev limiter around 2.5K and thirdly, it will stall coming up to a junction and then behave as if its run out of petrol, turn the key and it fires and then dies again. If you leave it for 30 seconds or so it starts and runs perfectly. Also when it is doing the "rev limiter" thing, if you quickly turn the ignition on and off while driving it clears immediately. Its had a Bosch coil recently, magnacor leads, plugs dizzy cap and rotor, all Lucas. I’m suspecting the ignition amp? Any thoughts?
First it will run fine and then not idle, you can press the clutch while driving and it will stall. Secondly it will suddenly behave as if its has a rev limiter around 2.5K and thirdly, it will stall coming up to a junction and then behave as if its run out of petrol, turn the key and it fires and then dies again. If you leave it for 30 seconds or so it starts and runs perfectly. Also when it is doing the "rev limiter" thing, if you quickly turn the ignition on and off while driving it clears immediately. Its had a Bosch coil recently, magnacor leads, plugs dizzy cap and rotor, all Lucas. I’m suspecting the ignition amp? Any thoughts?
I have a similar problem on mine. In the last few weeks it's developed symptoms similar to running out of petrol: when accelerating, it stutters, as though the fuel isn't getting through.
Following some searching on here, it sounds like it could be the coolant sensors, which is about 10-15 pounds.
The stepper motor should AFAIK only affect idling, but it also seems to affect acceleration.
I'm going to clean the stepper motor, but can anyone suggest a good place to get a coolant sensor mail-order??
Thanks!
Following some searching on here, it sounds like it could be the coolant sensors, which is about 10-15 pounds.
The stepper motor should AFAIK only affect idling, but it also seems to affect acceleration.
I'm going to clean the stepper motor, but can anyone suggest a good place to get a coolant sensor mail-order??
Thanks!
I've had the same trouble with my Chim in the past? It's 1995 plate, checked all those points mentioned, but still the same thing happening? Then I noticed that the bonnet braces were touching the alternator, when I went around a bend or over a bump (also had the engine mounts checked, solid)? Its like as if the brace was arcing against the alternator? So I put electrical tape around the brace to see if that would sort it & it has?? I haven't had any trouble since. I've noticed the later models have the braces built into the bonnet & are covered in fiberglass? Was this the reason why they covered them??
I was told by Dream Machines that you should never turn the engine off whilst the car is moving.
Prior to having a new starter to solve the hot start problem I declutched and turned he engine off whilst driving to see if it would start on the starter, thinking if it didn't I could re engage the clutch to start it.
It would then not start at all, and I sat at the side of the road having one of those "TVR" moments. Fortunately after about 5 mins it started. DM told me you can bu**er up the ECU by switching off whilst moving, its to do with the speed sensor I think they said
Prior to having a new starter to solve the hot start problem I declutched and turned he engine off whilst driving to see if it would start on the starter, thinking if it didn't I could re engage the clutch to start it.
It would then not start at all, and I sat at the side of the road having one of those "TVR" moments. Fortunately after about 5 mins it started. DM told me you can bu**er up the ECU by switching off whilst moving, its to do with the speed sensor I think they said
I had a similar problem with mine....was running fine for ages then started to run a bit 'lumpy'. Eventually it cut out at a roundabout. Turned key off then back on and it run for about 30secs before cutting out. Turned off back on again and it did the same.
Ended up undoing the petrol filler just a bit and it ran fine. Now i never fully tighten the petrol cap.
Probably not the problem but worth a try????
Just seems that everything you do to rectify the problem involves turning the ignition on and off which will make the fuel pump get the fuel up to pressure without the engine running.
Ended up undoing the petrol filler just a bit and it ran fine. Now i never fully tighten the petrol cap.
Probably not the problem but worth a try????
Just seems that everything you do to rectify the problem involves turning the ignition on and off which will make the fuel pump get the fuel up to pressure without the engine running.
had the same problem with my old E30 M3 and it turned out to be a split in the distributor cap - I only saw the slight sparking because the lights were out in the garage when I revved it from under the bonnet. A drop of wd40 and sealent on the cap solved it. So it could be something to do with the sparking circuit
Groomvroom,
Thought you may be interested in this extract from Steve Heath's bible. (page 105 if you have it)
Engine shutdown or gagging at 2500 rpm
The symptoms of this fault are that the engine will suddenly not rev above 2500 rpm when the throttle is opened. The engine then starts to cut out and cuts back in after 3-5 seconds.
* Faulty or misaligned throttle pot. Cleaning the connectors can sometimes cure this, although replacement is the only real option if the fault is with the track itself. Check that it is set up correctly and reaches the correct voltages when the throttle is fully open and closed.
* Faulty lambda sensor. This causes the ECU to create the wrong mixture, which causes bad running.
* Faulty temperature sensors. If these are not working correctly, the mixture can be incorrect, causing faulty running. In many cases, it shuts off the fuel and this causes the gagging. It's just like the rev limiter coming in. In other cases, the over rich mixture does not combust properly and this can upset the lambda sensor.
* Faulty injectors.
Hope this is of help to you and I'm not breaking anhy copyright stuff!!!
Nick
Thought you may be interested in this extract from Steve Heath's bible. (page 105 if you have it)
Engine shutdown or gagging at 2500 rpm
The symptoms of this fault are that the engine will suddenly not rev above 2500 rpm when the throttle is opened. The engine then starts to cut out and cuts back in after 3-5 seconds.
* Faulty or misaligned throttle pot. Cleaning the connectors can sometimes cure this, although replacement is the only real option if the fault is with the track itself. Check that it is set up correctly and reaches the correct voltages when the throttle is fully open and closed.
* Faulty lambda sensor. This causes the ECU to create the wrong mixture, which causes bad running.
* Faulty temperature sensors. If these are not working correctly, the mixture can be incorrect, causing faulty running. In many cases, it shuts off the fuel and this causes the gagging. It's just like the rev limiter coming in. In other cases, the over rich mixture does not combust properly and this can upset the lambda sensor.
* Faulty injectors.
Hope this is of help to you and I'm not breaking anhy copyright stuff!!!
Nick
Does this occur only when the fans kick in?
I ask because I also had very similar symptoms but only when the fans kicked in.
Turned out that the air intake pipe to the AFM had fallen off (or not put back on properly!) - when the fans kick in the ECU does something that requires air through the AFM - I wasn't getting any so the engine spluttered.
Once diagnosed it was a 2 second fix.
I ask because I also had very similar symptoms but only when the fans kicked in.
Turned out that the air intake pipe to the AFM had fallen off (or not put back on properly!) - when the fans kick in the ECU does something that requires air through the AFM - I wasn't getting any so the engine spluttered.
Once diagnosed it was a 2 second fix.
Ok, sorted it, the problem did come back, turned out to be two things, fitting a new ECU temp sensor sorted the "gagging" problem, the stalling turned out to be the stepper motor, I think I might have knackered it when I took it off trying to sort the first problem, swapped it with the one from my 4.3 and it iddled correctly. No damage visable and I did use ptfe tape to re-fitt it. The one on my 4.3 had a thick rubber washer. Shes up for sale now to pay for my engine rebuild.
Edited by groomvroom on Monday 23 October 19:33
Gassing Station | Chimaera | Top of Page | What's New | My Stuff